This invention relates generally to a method and apparatus for drying grain in storage, and more particularly, to a new and improved method and apparatus.
Over the years, it has become well-established that grain tends to spoil in storage, particularly when the moisture content of the grain is fairly high. For example, it has been found that the higher the moisture content within corn at harvest time, the more cracks and fines the corn will develop during the handling and drying. Furthermore, foreign material in turn makes it more difficult to keep the corn from deteriorating while in storage. At present, the losses of grain in storage, particularly corn, are minimized by taking certain precautions in handling of such grain.
It has been found that drying grain such as corn to below a 15% moisture content substantially minimizes the losses of the corn due to mold, bacteria, or other micro-organisms. In some instances, for example soft corn, it is desirable to dry the grain to approximately 131/2% moisture content. Furthermore, it is important that the moisture content throughout the grain storage bin be uniform. If not, molds can grow where there are pockets of moist grain. This is a prevalent problem since some mold spores develop in the field and are carried in to the grain storage bin.
Proper drying will arrest mold growth in the grain storage bin. For example, if the relative humidity of the grain is kept below 65%, molds develop very slowly, if at all. However, at a relative humidity of about 75%, mold growth is rather rapid and abundant. Furthermore, when mold develops, such as in a pocket located within the grain storage bin, a temperature of about 130.degree. F. can be reached. This high temperature can be noticed and detected by inserting a thermometer probe into the grain bed and taking a temperature reading. Another approach to detecting the elevation in temperature is to sense the temperature of the air coming out of the aeration fan at the top of the grain storage bin. This temperature should be about 100.degree. F. when everything is normal. As heat builds up within the storage bin, the sound kernels of corn will break down and become dark in color.
To overcome these problems, grain storage bins have been provided with means for drying the grain while it is in storage in grain elevators, and the like. However, such prior art grain drying apparatus and methods are rather complex and expensive. Generally, they require elaborate independent means for heating and drying the grain.